1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device using a slit mask capable of substantially preventing the formation of a backward sloping surface of an insulating layer, and a manufacturing method thereof.
2. Description of Related Art
An LCD device displays an image by controlling light transmittance of liquid crystal having dielectric anisotropy using an electric field. The LCD device is formed by assembling a color filter substrate on which a color filter array is formed and a thin film transistor (TFT) substrate on which a TFT array is formed, with liquid crystal disposed between the color filter array and the TFT array. A common electrode to which a common voltage is supplied is formed on the entire surface of the color filter substrate. A plurality of pixel electrodes to which data signals are individually supplied is formed in a matrix format on the TFT substrate. TFTs for individually driving the plurality of pixel electrodes, gate lines for controlling the TFTs, and data lines for supplying a data signal to the TFTs are also formed on the TFT substrate.
The TFT substrate has a multi-layered structure in which a plurality of conductive layers and insulating layers are stacked. For example, a first conductive layer for forming the gate lines, gate electrodes of the TFTs, etc., a second conductive layer for forming the data lines, source and drain electrode of the TFTs, etc., and a third conductive layer for forming the pixel electrodes, etc., are stacked on the TFT substrate with insulating layers disposed between the conductive layers.
A plurality of contact parts for connecting the first and second conductive layers by using a bridge electrode formed of the third conductive layer exist on the TFT substrate. The bridge electrode connects the first and second conductive layers through a first contact hole exposing the first conductive layer by penetrating at least two insulating layers and through a second contact hole exposing the second conductive layer by penetrating at least one insulting layer. An edge of an upper insulating layer of the at least two insulating layers penetrated by the first contact hole may have a backward sloping surface due to over-etching. The backward sloping surface may result in an open defect of the bridge electrode through the first contact hole. Even if the bridge electrode is not opened, moisture may penetrate through an unfastened gap of the upper and lower insulating layers and progressively increases the resistance of the bridge electrode, thereby lowering picture quality.